In a new kind of vocational training school being housed in a Boston basement, Katy Feng says she’s working harder than she ever did at Dartmouth College. Graduating last year, the 22-year-old received her bachelor’s degree in psychology and studio art, and it cost more than a quarter-million dollars.

NOTE: Anyone interested in learning to code, DaVinci Coders offers multiple courses designed to get you into the rapidly growing technology industry. For more info please visit davincicoders.com.

She sent out dozens of résumés looking for a full-time job in graphic design but wound up working a contract gig for a Boston clothing store. “I thought, they’ll see Dartmouth, and they’ll hire me,” Feng says. “That’s not really how it works, I found.” She figures programming is the best way to get the job she wants. Hence the basement, where she’s paying $11,500 for a three-month crash course in coding.

Feng sits in the class five days a week from 9 a.m. to 5:30 p.m., tapping on a laptop and squinting at the syntax of the programming languages JavaScript and Ruby. Homework swallows her nights and weekends—a big change from Dartmouth, where after a few hours of class “you could just do whatever,” Feng says. “This is definitely like, you’re doing it all day long.”

Feng is among thousands of students, about 70 percent of whom already have college degrees, flocking to coding boot camps. Hers is run by a company called General Assembly that promises to transform “thinkers into creators,” not to mention holders of well-paying jobs. It’s an especially attractive pitch for humanities and social sciences majors who didn’t learn the skills they need to compete for the plentiful jobs in the technology industry.

Four years ago, General Assembly was among the first of these training schools; now there are more than 80. About 6,000 students graduated from a coding boot camp in 2014, triple the previous year, says Course Report, a website that lets students rate the various courses. The schools took in a combined $59 million in revenue, or about $9,833 per student, estimates Course Report co-founder Liz Eggleston.

Code-camp students don’t get a diploma they can hang next to an Ivy League one, but they come away with projects they can show off in interviews, typically apps. Six months after finishing, 59 percent report a salary increase, averaging $23,000 annually, according to SwitchUp, another rating site. “They do seem to be effective at helping their candidates win entry-level tech jobs,” says Tyler Willis, a spokesman for tech headhunter Hired. Jensen Bouzi, Amherst College class of 2014, finished at Dev Bootcamp in December and by March had a coding job at Avrett Free Ginsberg, a New York ad agency. “This is the best way to go in terms of getting a foot in the door,” Bouzi says.

Dev Bootcamp, now owned by Kaplan, the SAT-prep and education company, was founded in San Francisco by a former Microsoft engineer; it also operates in New York and Chicago. General Assembly started as a co-working space in New York’s Flatiron district in 2011 and evolved into boot camps in 13 cities across the U.S., U.K., Australia, and Hong Kong. The startup has raised $49.5 million from the likes of Jeff Bezos and Russian e-mail billionaire Yuri Milner. City No. 14, it says, will be Singapore.

The biggest concentration of schools remains in California, and some, including Dev and Hack Reactor, have established another source of revenue. They’ve cut deals with employers such as tech-industry PR firm Cision, promising an early crack at top graduates in exchange for fees worth 10 percent of each new employee’s first-year salary. Hackbright Academy in San Francisco, which enrolls only women, is a feeder for Facebook and Pinterest. The schools tailor programs to industry needs, says Harsh Patel, a former grade-school math and science teacher who co-founded boot camp MakerSquare. By contrast, he says, “Colleges are preparing students for things that employers were hiring for 15 years ago.”

The boot camps don’t guarantee employment to graduates, and some students struggle to finish. Fifteen stories above Wall Street, students in Dev’s open-plan office break only for lunch and occasional snacks, which they store in plastic bins. Alex Homer, who graduated from Tulane University in 2013 with a degree in English, says he found Dev’s pace exhilarating but fell ill while toiling 14 hours a day on his final project, though he did finish. Those who can’t keep up can be held back or even kicked out. “I need time to learn, and this didn’t fit the way I learn best,” says Vivek Ratkalkar, 26, a Pace University communications graduate who was asked to leave Dev in March.

In lieu of tuition, App Academy makes students agree to fork over 18 percent of their first year’s pay. A 12-week boot camp at Hack Reactor in San Francisco costs $17,780; that’s $1,482 a week, about the same as a week’s worth of tuition at Harvard. The cost covers an 11-hour, six-day-a-week program that has led many to jobs at companies such as Facebook and Google, says Hack Reactor co-founder Shawn Drost.

The boot camps offer a coding curriculum that’s more accessible than those at many colleges, says Anna Taberski, an alumna of Dev’s New York school who now codes for Web designer Blenderbox. She graduated in 2012 from the University of California at Berkeley, which has a top-ranked computer-science program, but she found the programming classes there forbidding. Instead of comp sci, she majored in comp lit. “I think it’s clear that there was something missing at Berkeley,” she says. The university says it added a more accessible computer science course, the Beauty and Joy of Computing, in 2010 and is considering an even more basic offering.

Back in the Boston basement, Katy Feng is working on her final project, an app that helps users personalize their websites with photos and news sources. Dartmouth says employers highly value its graduates, 90 percent of whom headed to paying jobs, grad school, or volunteer positions in 2014. Feng says General Assembly has given her practical training she didn’t get at Dartmouth. “Your day-to-day job, you’re probably not going to learn that in college. This is where you learn how to do it.”